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Re: [OWLWG-COMMENT] Punning and the "properties for classes" use case

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Mon, 05 Nov 2007 06:13:07 -0500 (EST)
Message-Id: <20071105.061307.122263646.pfps@research.bell-labs.com>
To: danny.ayers@gmail.com
Cc: schneid@fzi.de, public-owl-dev@w3.org

From: "Danny Ayers" <danny.ayers@gmail.com>
Subject: Re: [OWLWG-COMMENT] Punning and the "properties for classes" use case
Date: Mon, 5 Nov 2007 10:48:39 +0100

> Hi Peter,
> 
> I'd be grateful if you could help me with this one point -
> 
> On 02/11/2007, Peter F. Patel-Schneider <pfps@research.bell-labs.com> wrote:
> 
> > Well, RDF overloads URIs already.  A URI in RDF denotes a entity in the
> > domain of discourse as well as that entity's property extension, which
> > also carries the entity's class extension.
> 
> I assumed the resource identification here was (very loosely) like
> saying 'that bag of peanuts' - the peanuts inside are an implicit
> characteristic of the thing identified, even though you might not be
> able to see them. Perhaps you could contrast RDF's approach with
> another (OWL 1.1's?) which doesn't overload?
> 
> Cheers,
> Danny.

Well OWL DL and OWL 1.1 overload as well, at least in some sense.

OWL DL with separated vocabularies does not overload this way (pretty
much).  A URI can denote only one of an individual, a property, or a
class.

Many treatments of set theory do not overload this way.  Elements of the
domain of discourse *are* sets, not individuals that have associated
sets.  This does not prevent the set elements of the domain of discourse
from participating in arbitrary relationships, of course.

The distinction is to a large extent not particularly interesting, at
least as far as I am concerned.  What does it matter that in some
contexts a URI is an individual and in others it is a class?    If one
wants a single denotation for a URI one can finess the difference in
multiple ways, e.g., the RDF way or considering the single denotation to
have several components.  

peter
Received on Monday, 5 November 2007 11:24:06 GMT

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